the cli should notify the user if there are updated core plugins

We only nag about cli versions, and that is set at a frequency that will not annoy.
https://github.com/oclif/plugin-warn-if-update-available

## Expected

You might be using outdated plugins, and the cli gives you a notice if there are updated core plugins.

## Actual

You might be using outdated plugins, and the cli does not give you a notice if there are updated core plugins.

## Workaround

Use `aio update --list`
Then, if there are updates, reinstall the cli which should pick up the new core plugins.

Note: This `aio update` command will only update user-installed plugins that are not core